Notes on Raveen Kumar

Adding epiog to python scripts using argparse module

Mon, 20 Feb 2023 00:00:00 +0000

https://docs.python.org/dev/library/argparse.html#argparse.RawDescriptionHelpFormatter

We can add epilog to argparse help and description to add more info. Refer link above.

PHP Notes

Mon, 20 Feb 2023 00:00:00 +0000

PHP Notes

Coding Guidelines

Sat, 18 Feb 2023 00:00:00 +0000

First rule of coding, do not code
Second rule of coding, write less code whenever you can

Fighting techniques

Sat, 18 Feb 2023 00:00:00 +0000

Structure is key to success

Windows WSL Notes

Sat, 18 Feb 2023 00:00:00 +0000

https://thomasward.com/wsl2-x11/

Change password

To change to root user

ubuntu config --default-user root

To change password

passwd, passwd <user_name>

Open Windows GUI applications with Linux command line

mspaint.exe file.png
notepad.exe file.txt

https://dev.to/adityakanekar/upgrading-from-wsl1-to-wsl2-1fl9

C++ notes

Fri, 17 Feb 2023 00:00:00 +0000

For loops

for (uint32_t i=0; i<10; i++) {
printf("i = %d", i);
}

Prints

printf(“unsigned = %u”, var1); printf(“signed = %d”, var1);

Functions

https://softwareengineering.stackexchange.com/questions/286490/what-is-the-difference-between-function-and-functionvoid 6.7.6.3 Function declarators (including prototypes) 10 The special case of an unnamed parameter of type void as the only item in the list specifies that the function has no parameters. 14 An identifier list declares only the identifiers of the parameters of the function. An empty list in a function declarator that is part of a definition of that function specifies that the function has no parameters. The empty list in a function declarator that is not part of a definition of that function specifies that no information about the number or types of the parameters is supplied.145)

Documentation notes

Fri, 17 Feb 2023 00:00:00 +0000

Errors and bugs

Fri, 17 Feb 2023 00:00:00 +0000

Removing old name: Device or resource busy

https://unix.stackexchange.com/questions/11238/how-to-get-over-device-or-resource-busy

The tool you want is lsof, which stands for list open files.

It has a lot of options, so check the man page, but if you want to see all open files under a directory:

lsof +D /path

That will recurse through the filesystem under /path, so beware doing it on large directory trees.

Once you know which processes have files open, you can exit those apps, or kill them with the kill(1) command.

Finance

Fri, 17 Feb 2023 00:00:00 +0000

General programming notes

Fri, 17 Feb 2023 00:00:00 +0000

File structure

Always try to keep files in one directory, but name them properly
Use multiple directories to dump similar data

json

Cannot use bash variables inside json files

Linux notes general

Fri, 17 Feb 2023 00:00:00 +0000

Commands

cat - contatenate
tac - concatenate in reverse

`column` command

The column utility formats its input into multiple columns.

printf "a:b:c\n1::3\n" | column -t -s ':'

a	b	c
1	3

Note that this output is different from one that is printed in terminal. Strange… Below is the terminal output.

a	b	c
1		3

`uuidgen` universal unique id generator

Generate unique ID’s

`script` Records terminal

man script
man scriptreplay

Example

script --timing=file.tm script.out
# Write some scripts
# Exit with `exit` or `^d`
scriptreplay --timing file.tm --typescript script.out

`reset` Recover a borked terminal

Count number of files in a directory

ls -1 | wc -l

Building from source

./configure
./configure --prefix=$path

Redirections

2>&1
2>&1 > /dev/null
>
>/dev/null
>>

Keymaps

Ctrl-c
Ctrl-d
Ctrl-l

cp

cut

less

linux

seq

paste

pstree

du

rsync

sed

ssh

vifm

zip

Readline

C-x C-e to edit current commant in default text editor
or v in vi mode

`ldd` Print shared libraries

This command can be used to find all the shared library or libraries of a program

Programming Concepts

Fri, 17 Feb 2023 00:00:00 +0000

Arrays
Associative arrays
dicts
case
while
for
if
exit codes and returns
advicing functions
Fuzzy matching - Fuzzy Matching with python

Programming quotes

Fri, 17 Feb 2023 00:00:00 +0000

How to shoot yourself in the foot

The problem with object-oriented languages is they’ve got all this implicit environment that they carry around with them. You wanted a banana but what you got was a gorilla holding the banana and the entire jungle. — Joe

Some people, when confronted with a problem, think ‘I know, I’ll use regular expressions.’ Now they have two problems.

Jamie Zawinski

Yuan-Ma said, ‘When you cut against the grain of the wood, much strength is needed. When you program against the grain of the problem, much code is needed.’

Simulations

Fri, 17 Feb 2023 00:00:00 +0000

Notes on compiling a testbench with irun. The file list it compiles lives in irun_args_compile.

Add every new file to `irun_args_compile`

A new file stays out of the compile until you list it there.

Don’t compile a file or directory twice

Listing the same file or directory twice stops the compile with one of these errors:

xmvlog: *E,COFILX
xmvlog: *E,ILLPDL

Don’t `include a file that is already compiled

If irun_args_compile already compiles a file, the .sv file doesn’t need to `include it again.

ssh

Fri, 17 Feb 2023 00:00:00 +0000

Cd to a particular dir after ssh

$ ssh -t ostechnix@192.168.225.52 'cd /home/ostechnix/dir1 ; bash'

To automatically install a ssh public key on a remote machine

ssh-copy-id -i ~/.ssh/id_rsa.pub $USER@$HOSTNAME

To manually install a ssh public key on a remote machine

cat ~/.ssh/id_rsa.pub; # copy the contents of the file; paste into ssh/authorized_keys file;
chmod 600 ~/.ssh/authorized_keys

Emacs

Thu, 16 Feb 2023 00:00:00 +0000

You mean Vim?

No matter how much I try EMACS is just too slow for me. Its not snappy as vim. and often times its lagging and hanging and the package management is too slow. Its bluky and full of bloat. Dont get me wrong the base emacs is great. But as soon as I add packages and try to modify it, it keeps getting bulkier and difficult to manage. Whereas vim is snappy. And I can full use tmux and terminal and my hands and safe from injuries. And its comfy.

VLSI

Thu, 16 Feb 2023 00:00:00 +0000

VLSI

GNU Make Notes

Mon, 13 Feb 2023 00:00:00 +0000

GNU Make notes

https://www.cmcrossroads.com/article/basics-getting-environment-variables-gnu-make

exit script with exit 0 or make will interpret it as error if there is no 0 returned. Context below

c - Make: *** [] Error 1 - Stack Overflow

Notes on Raveen Kumar

Adding epiog to python scripts using argparse module

PHP Notes

PHP Notes

Coding Guidelines

Fighting techniques

Windows WSL Notes

Change password

To change to root user

To change password

Open Windows GUI applications with Linux command line

C++ notes

For loops

Prints

Functions

Documentation notes

Errors and bugs

Removing old name: Device or resource busy

Finance

General programming notes

File structure

json

Linux notes general

Commands

column command

uuidgen universal unique id generator

script Records terminal

Example

reset Recover a borked terminal

Count number of files in a directory

Building from source

Redirections

Keymaps

Readline

ldd Print shared libraries

Programming Concepts

Programming quotes

Simulations

Add every new file to irun_args_compile

Don’t compile a file or directory twice

Don’t `include a file that is already compiled

ssh

Cd to a particular dir after ssh

To automatically install a ssh public key on a remote machine

To manually install a ssh public key on a remote machine

Emacs

VLSI

VLSI

GNU Make Notes

GNU Make notes

`column` command

`uuidgen` universal unique id generator

`script` Records terminal

`reset` Recover a borked terminal

`ldd` Print shared libraries

Add every new file to `irun_args_compile`